This research project
was initiated in January of 1997 as a response to a frequently asked question
by agencies that use our services. How, we are asked, do the dogs define death?
At what point during the decomposition process of a human body will the dogs
demonstrate that they recognize the scent as post-mortem?

We set up this
research project to begin to understand when and how our dogs can discriminate
live scent from post-mortem scent. All of the dogs used in this project have
been "cross-trained", that is trained in both the discipline of finding
and indicating on live human scent and also on post-mortem (cadaver) scent.
*

The general medical
definition of death, "The irreversible cessation of respiratory and heart
activity" (Spitz and Fisher, 1993), describes the exact moment a human
being becomes a dead body. Physiologic changes begin immediately, and within
the first two hours after death onset of lividity, chemical changes in the blood,
relaxation of muscle tissue, and other changes have been documented. In fact,
in some cases, lividity can be seen as soon as 15 minutes post-mortem. Between
2-4 hours after death, body temperature begins to drop (Haglund and Sorg, 1997),
chemical changes in muscles begin and autolysis advances.

We want to begin
to learn, understand, and document the minimum post mortem time interval for
which our dogs can perceive the difference between live and dead scent. Our
window into the vivid realm of canine olfaction is, obviously, the dog's body
language and more precisely, the alert sequence. The dog uses the alert to intentionally
communicate to us "I have found a smell that you want". We want to
know the minimum interval at which our dogs can classify a scent as dead, as
opposed to live, and when that classification is distinct enough that the dog
is moved to perform the trained alert.

*All post-mortem
scent samples consist of sterile gauze pads, (sealed until just prior to use)
placed on abdominal area of decedent for exactly 20 minutes. Gauze pads are
then placed in unused plastic bags and double sealed with packing tape. All
post-mortem scent samples are handled with latex gloves, and at no time do these
samples come in skin contact with live human scent.
*All Live Human scent samples are placed on the abdominal area of a living person
for exactly 20 minutes, then placed in unused plastic bags and double sealed
in the same manner as the post-mortem samples.

All trials are conducted using a lineup method:
Each consists of a line of three gauze pads - one exposed to post-mortem scent,
one exposed to live human scent, and one sterile unused pad opened with gloved
hands just prior to each trial.
All trials are done on a hard surface, either asphalt, cement, or hard packed
dry dirt ground.
Each dog is given the "cadaver" command by its handler and walked
through the lineup. The dog is then asked to choose and indicate to the handler
which gauze contains post-mortem scent.
Every trial was "blind" to each handler working it, that is the handler
had no prior knowledge of lineup sequence.
Dogs are given only a single choice per trial.
Choices are recorded as CORRECT or INCORRECT only.
Any dog that appeared unwilling to commit to a single sample was removed from
that trial and the choice was recorded as Incorrect.
All samples are properly disposed of after each trial.

TRIALS BEGUN: January 1997
NUMBER OF DOGS USED: Five different dogs
POST-MORTEM INTERVAL RANGE: From 70 minutes to 3 days
NUMBER OF TRIALS COMPLETED: As of July 1997, total of 52 trials completed
PRELIMINARY RESULTS: The shortest post-mortem interval for which we received
a correct response was one hour and 25 minutes. However, the post-mortem interval
for which we received a consistently correct response from all dogs involved
is 2.5 - 3 hours.

NOTES:
We emphasize our inability to control all variables during our project. It has
been impossible for us to obtain scent samples and carry out the trials under
strictly controlled conditions. We had no control over the environmental conditions
under which our samples were gathered, manner and cause of death, nor could
we exercise tight regulation over the quantity of samples of any one given time
interval. Since there are periods in which our samples are few and far between,
this project has no set deadline and will be ongoing for a time. Our intention
is not to offer an absolute answer to the questions posed, but to initiate an
ongoing dialogue and offer what we hope is a point of departure for other exciting
research projects. This will shed light on the under-navigated and sometimes
mysterious arena of canine olfaction applied to body recovery.

It is important to note what the dogs are not being asked to
do, as well as what they are being asked to do. They are not choosing from a
lineup of actual human tissue, but only from gauze pads for which great care
has been taken to expose them only to dry skin regions, not to any blood or
perceivable body fluids. Also note that the exposure time is exactly 20 minutes.

In addition, there are many obvious variables not addressed
by this project. It will be exciting to undertake future studies that deal with
such factors as difficulty of detection according to age, sex, and race of decedent
and manner and cause of death.

Comments, suggestions and questions regarding this project are
welcome.